Strangles Bacterial Culture
Pathogen test The bacterial culture will be reported positive if a beta-hemolytic Streptococcus species is grown and identified specifically as...
£27.00
Sample Requirements
Live Strep equi organisms must be recovered by a swab or wash of the nasopharynx, nasal passages, or draining abscesses.
Send your sample by regular mail or express delivery to:
Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal
Turnaround Time
2 to 5 working days
About the test
This bacterial culture detects viable Streptococcus equi subsp. equi, the bacterium responsible for Strangles. A positive culture confirms the presence of live bacteria and supports the diagnosis of active infection.
Why test?
Testing is recommended to:
- Confirm active Streptococcus equi infection.
- Diagnose horses with suspected Strangles.
- Identify infected horses during outbreaks.
- Detect bacterial shedding in recovering horses.
- Support treatment decisions and biosecurity measures.
How it works
🛒 Purchase the Test: Select and buy the test online.
📧 Receive Instructions: After payment confirmation, receive instructions for sample collection.
✨ Sample Collection: Your veterinarian collects the appropriate swab or wash sample.
📄 Download Submission Form: Download the printable submission form.
📮 Send Samples: Send your samples by regular mail or express delivery to:
Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal
📄 Receive Results: Get your laboratory report by email.
Clinical signs
- Classic clinical signs include a fever (often >103°F or 39.5°C) first, followed by one or more of the following symptoms: depression, thick nasal discharge and lymph node enlargement under the jaw and/or in the throat latch region. The abscessed lymph nodes may drain externally or into the guttural pouches (blind-end sacs connected to the throat in horses) resulting in nasal discharge. Horses that have been vaccinated for strangles or horses that have previous partial immunity may develop milder signs of upper respiratory tract infection.
- Bastard strangles cases may develop colic signs, fever, and/or weight loss with or without a history of previous strangles disease or exposure. Horses with purpura hemorrhagica may develop edema of the head, trunk, and/or legs; and broken blood vessels or bruising of the mucous membranes of the mouth, eyes and nose. Additional signs can include fever, severe depression, and muscle tightness. The severity of symptoms in purpura hemorrhagica cases ranges from mild to life-threatening.
Transmission
Strangles is caused by oral exposure of a horse to S. equi bacteria. Once within the oral cavity, the bacteria invade the tonsils and subsequently colonize the lymph nodes.
Bacteria can be transmitted through contact with pus or nasal discharges from an infected horse, or from contaminated bedding or barn equipment (water troughs, buckets, etc.).
Flies may also act as vectors, spreading the bacteria from horse to horse.
Under the right conditions, S. equi can survive in the environment for weeks or months.
Exposure of a horse to S. equidoes not necessarily mean that it will come down with strangles. Factors that influence the risk of disease include dose of bacteria (poor sanitation and direct contact with nasal secretions and pus increase the chance of disease); immune status of horse. Previously exposed horses are often immune to the disease, or do not get as sick as unexposed horses. During the first three to six months of life, foals are often protected by maternal antibodies. Vaccination can also increase resistance to the disease; stress (poor nutrition, overcrowding, lengthy transportation or pre-existing diseases increase the risk of strangles).
Strangles may be transmitted by “silent shedders” who do not display signs of disease. These horses commonly carry the strangles organism in the guttural pouch, an air sac at the back of the horse’s throat. Detection of these animals requires guttural pouch endoscopy (passing an endoscope via the horse’s nose into the guttual pouch). Strangles is most commonly transmitted by acutely ill or recovering horses that are still shedding bacteria in their nasal secretions. Bacterial culture results have a turnaround time of 2 to 3 days. The DNA test known as Polymerase Chain Reaction (PCR) takes less than a day. However, it may take an additional 1 to 2 days to send samples to the laboratory.
Prevention
- Biosecurity on the farm is necessary to prevent spread of disease.
- Isolate new horses for three weeks prior to introducing them to the rest of the population.
- Isolate any horse with a fever and signs of strangles.
- Do not share tack or equipment between sick horses and others
- Perform twice daily monitoring of rectal temperatures of all horses in an outbreak to identify new cases.
- Stop all movement of horses to and from farm when strangles is identified.
- Disinfect water buckets daily.
- Use strict hygiene between horses to reduce spread of the disease.
- Ideally, three throat flush samples are obtained from recovering horses and any horses who were in contact with sick horses at approximately weekly intervals and tested forS. equisubsp equi by PCR and culture. Identification of strangles bacteria in clinically recovered horses may mean the guttural pouches have retained some infection. Endoscopy of the guttural pouches provides visualisation of any pus or dried debris (chondroids) that harbor the bacteria. A small number of horses will recover from strangles and continue to shed bacteria from the guttural pouch, causing recurrent farm outbreaks. Detection and treatment of these “silent carriers” (S. equibacteria in guttural pouches) via endoscopy and PCR is essential for preventing disease recurrence on a farm.
- Discuss vaccination types and recommendations with your veterinarian. Vaccination does not provide 100% immunity againstS. equiinfection. Vaccination is not recommended during or within two years of a strangles outbreak due to the increased risk of purpura hemorrhagica.
Results
The bacterial culture reports one of the following:
- Positive: Live Streptococcus equi subsp. equi was isolated from the submitted sample, confirming active infection.
- Negative: No Streptococcus equi subsp. equi was isolated from the sample.
Negative culture results do not completely exclude infection, particularly if bacterial shedding is intermittent or antibiotics have been administered before sampling.
Additional information
Bacterial culture remains a valuable method for confirming active Strangles infection by isolating viable organisms. Although PCR is generally more sensitive, culture provides definitive evidence of live bacteria and may be used alongside molecular testing during disease investigations and outbreak control.
FAQs
Which horses should be tested?
Horses showing fever, nasal discharge, enlarged lymph nodes, draining abscesses or suspected Strangles should be tested. Culture may also be used during outbreak investigations.
Which samples are accepted?
Nasopharyngeal swabs, nasal swabs, guttural pouch washes or swabs collected from draining abscesses.
What does a positive culture mean?
A positive result confirms the presence of live Streptococcus equi bacteria and supports a diagnosis of active Strangles.
Can a negative culture rule out Strangles?
No. Negative results may occur if bacteria are present in low numbers, shedding is intermittent or antibiotics were administered before sampling. Additional testing, such as PCR, may be recommended.
When will I receive my results?
Results are available within 2 to 5 working days after sample arrival at the laboratory.